Rapydan Topical Anaesthesia for Arterial Cannulation

This study has been completed.

Sponsor:

Medical University of Vienna

ClinicalTrials.gov Identifier:

NCT01494311

First Posted: December 16, 2011

Last Update Posted: March 18, 2013

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Arterial catheterization is painful and is associated with patient stress and anxiety. Analgesia is usually provided by subcutaneous injection of local anesthetic. An alternative is topical anaesthesia, such as Rapydan which is a novel topical anesthetic patch containing 70 mg each of lidocaine and tetracaine. We therefore tested the hypothesis that Rapydan patch analgesia is non-inferior to subcutaneous local anesthetic.

Further study details as provided by Kurt Rutzler, Medical University of Vienna:

Primary Outcome Measures:

Pain during arterial catheterization [ Time Frame: During and minutes after arterial cannula insertion, day 1. ]

After finishing the puncture procedure, patients were asked to rate their worst pain during subcutaneous injection, during insertion of arterial cannula, and one minute after catheter insertion using a 100-mm-long visual analog scale (VAS). The use of a VAS to measure pain and discomfort has been validated in the several settings of chronic pain, acute postoperative pain, and acute non-surgical pain.

Secondary Outcome Measures:

Pain during annethetic/saline injection. [ Time Frame: During and minutes after injection, day 1. ]

After finishing the puncture procedure, patients were asked to rate their worst pain during subcutaneous injection, during insertion of arterial cannula, and one minute after catheter insertion using a 100-mm-long visual analog scale (VAS).

Blood concentration of plasma tetracaine [ Time Frame: Minutes before and after patch application, day 1. ]

Investigator's evaluatuion of pain during catheter insertion [ Time Frame: At conclusion of procedure, day 1. ]

Investigators who were unaware of the randomization estimated each patient's pain intensity at the time of catheter insertion on a four-point scale with 0 indicating no pain and 3 indicating severe pain.

Difficulty of puncture [ Time Frame: During catheter insertion, day 1. ]

The difficulty of the puncture was assessed using a 5-point scale with 1 being insertion at first attempt through 5 which indicated failure to insert the catheter.

Number of punctrue attempts [ Time Frame: During catheter insertion, day 1. ]

The number of puncture attempts were documented by the investigator.

Incidence of edema and erthema at the patch site [ Time Frame: Evaluated immediately after patch removed, day 1. ]

After the patches were removed an investigator, blinded to the study randomization, evaluated the treatment sites for skin reactions including edema and erythema using a 5-point Likert scale (1 = none; 5 = vigorous).

Fourty-five patients were randomly assigned to receive a placebo patch, looking identically to the Rapydan patch and subsequent subcutaneous injection of 0.5 ml of lidocaine 1%.

Drug: Placebo Patch

A placebo patch was placed on each patient's wrist in the region of the maximum radial artery pulsation. After 20 minutes, the patch was removed.

Drug: Subcutaneous injection of 0.5 ml Lidocain 1%

After removing the patch, a blinded investigator injected 0.5 ml of 1% lidocaine solution. Three minutes after injection, an attempt was made to cannulate the radial artery with a 20-gauge catheter.

Experimental: Lidocaine/tetracaine patch

Fourty-five patients were randomly assigned to receive a lidocaine/tetracaine patch, followed by subcutaneous injection 0.5 ml of normal saline solution.

Drug: Lidocaine/tetracaine patch

The lidocaine/tetracaine patch topical anesthetic patch contains 70 mg each of lidocaine and tetracaine. The central area of each patch consists of a Controlled Heat Assisted Drug Delivery pod which is designed to warm the skin to 26-34°C, theoretically enhancing drug absorption and allowing application just 20 minutes before percutaneous procedures. A active or placebo patch was placed on each patient's wrist in the region of the maximum radial artery pulsation. After 20 minutes, the patch was removed.

Other Names:

Rapydan

Synera, 76667213

Drug: Subcutaneous injection of saline

After removing the patch, a blinded investigator injected 0.5 ml saline solution. Three minutes after injection, an attempt was made to cannulate the radial artery with a 20-gauge catheter.

Detailed Description:

Many clinical procedures including arterial and venous punctures, percutaneous venous catheter insertion, lumbar puncture, and dermatological procedures are associated with pain and consequent patient discomfort.1-2 With the exception of venopuncture, arterial puncture is the most common invasive procedure performed on critically ill patients. Also, it is often necessary before induction of anaesthesia for invasive measurements of blood pressure and collection of arterial blood samples in patients undergoing major cardiac surgery. Injection of local anesthetics before insertion causes intra-dermal turgor and can trigger local vasoconstriction, both of which reduce puncture success rate.

An alternative approach is to use topical anesthesia for percutaneous procedures. However, intact skin presents a significant barrier to topical anesthetic preparations. Therefore, topical anesthetic preparations typically must be applied under occlusive dressings for 45-60 minutes before vascular access — which is often longer than is clinically practical.

Rapydan (also known as Synera in the United States) is a novel topical anesthetic patch that contains 70 mg each of lidocaine and tetracaine. The central area of each Rapydan patch consists of a Controlled Heat Assisted Drug Delivery pod which is designed to allow for application just 20 minutes before percutaneous procedures. However, the efficacy of Rapydan topical analgesia has yet to be quantified for the more intense pain resulting from arterial puncture. We thus compared routine analgesia (subcutaneous injection with 0.5 ml of 1% lidocaine) with heated lidocaine/tetracaine patches. Specifically, we tested the hypothesis that lidocaine/tetracaine patch analgesia is non-inferior to that provided by subcutaneous lidocaine injection for insertion of arterial catheters.

Ninty patients undergoing elective major cardiac surgery were included in this prospective, double blind clinical trial. Patients were randomly assigned to receive either a lidocaine/tetracaine patch, followed by subcutaneous injection 0.5 ml of normal saline solution or placebo patch, looking identically to the Rapydan patch and subsequent subcutaneous injection of 0.5 ml of lidocaine 1%. Pain during arterial catheterization using 100-mm-long visual analog scale (VAS) was the primary outcome. Other outcomes were pain during anesthetic/saline injection and plasma tetracaine concentrations.

VAS pain scores during arterial puncture were comparable in both groups and Rapydan was non-inferior to subcutaneous lidocaine. Pain scores at the time of subcutaneous injection were significantly lower (better) in patients assigned to the lidocaine/tetracaine patch than to lidocaine (P = 0.001). Plasma tetracaine concentrations never exceeded the detection limit of 25 ng/ml at any time in any patient.

Both the lidocaine/tetracaine patch and subcutaneous injection of lidocaine provided comparable pain control during arterial catheter insertion. Subcutaneous lidocaine caused discomfort during injection whereas the lidocaine/tetracaine patch required placement 20 minutes before the procedure. Given adequate time, the patch provided better overall analgesia by obviating the need for subcutaneous infiltration.

Eligibility

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